The Kellgren and Lawrence system is a common method of classifying the severity of osteoarthritis (OA) using five grades. grade 0 (none): definite absence of x-ray changes of osteoarthritis grade 1 (doubtful): doubtful joint space narrowing and possible osteophytic lipping grade 2 (minimal): definite osteophytes and possible joint space narrowing grade 3 (moderate): moderate multiple osteophytes, definite narrowing of joint space and some sclerosis and possible deformity of bone ends grade 4 (severe): large osteophytes, marked narrowing of joint space, severe sclerosis and definite deformity of bone ends. Surgery is required is not only depends on grade but also on pt requirements and activity level. Most of the time grade 3&4 is required for surgery.

Decision for surgery and selection of  exact procedure depends on the requirement of  each patient. Discuss with your doctor your problem in details and let him decide the exact treatment for you.

There are 4 grades. Xray is sufficient to grade knee osteoarthritis Later Grade 3 and Grade 4 mostly need surgeries varying from HTO, Arthroscopic procedures to Total or Partial knee replacement .